Pneumatic hammer or like percussion-tool.



H. S. B. BRINDLEY.

PNEUMATIC HAMMER OR LIKE PERCUSSION TOOL.

APPLICATION FILED FEB. 17. 1913.

Patented Feb. 29,

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with the invention shall be practically HARRY SAMUEL BIGKERTON BRINDLEY, OF \VESTMINSTEB, LONDON, ENGLAND, ASSIGNOB. TO BOILER SCALERS LIMITED, GF VJESTMINSTER, LONDON, ENGLAND.

Specification of Letters Patent.

Patented Feb. 29, 1916.

Application filed February 17, 1913. Serial No. 7%,986.

To all whom it may concern:

Be it known that LHARRY SAMUEL BICK- ERTON BRINDLEY, a subject of the King of Great Britain and Ireland, and residing at Queen Annes Chambers, Westminster, London, S. 7., England, have invented certain new and useful Improvements in Connection with Pneumatic Hammers or like Percussion-Tools, of which the following is a specification.

lhis invention relates to improvements in pneumatic hammers or like percussive tools of the so-called valveless type with more particular reference to that class of device, the diameter of which is restricted by reason of the confined space such as a hole or tube in which it is required to operate.

In such cases it has been proposed to arrange the pneumatic tool in such a manner that the working fluid can act simultaneously on a plurality of surfaces of the hammer in order to increase the strength of the blow that may be delivered thereby without having to resort to an unnecessarily large diameter, but such devices have been complicated in construction and have usually involved an unnecessary large number of joints or surfaces through or past which leakage of the fluid is liable to take place, while the complicated construction of the devices renders it unsuitable for use by any but the most skilled operators.

The object of the present invention is to devise an improved form of device of the above nature having all the advantages of the known devices without their attendant disadvantages, and being of such a simple construction thatthe devices in accordance foolroof.

l/Vith this and other objects in view the invention consists in the novel features hereinafter described 'andmore particularly referred to in the appended claims.

The accompanying drawings illustrate two modes of carrying out the invention.

Figure 1 is a longitudinal sectional elevation showing one convenient construction of tubecleaning device in accordance with I so as to drive the my invention. Fig. 2 is a similar view illustrating a modified form.

In carrying my invention into effect in one convenient manner as, for example, in its application to apparatus for cleaning or scaling boiler tubes I provide a cylinder (4 within which the hammer or like device 73 is free to work, being a working fit within an internal shoulder 0 upon the cylinder dividing the latter into two portions and the hammer b I provide with the working or striking head (Z and a rear head 6 so arranged that the pressure of air or other medium is free to act in conjunction upon both piston heads. The compressed air or other medium is caused to enter a sleeve or extension f at the rear end of the cylinder a and of such size that an annular space 9 is provided between the sleeve and the cylinder into which space the air enters and from which it may escape into the cy inder by a suitable port or ports h arranged at or near the rear face of the internal shoulder a. The after-head 6 upon the piston is so arranged that there is always a certain amount of pressure tending to force the piston b rearwardly within the cylinder but when the piston has moved a sufficient distance in the cylinder a slot or slots 2' within the annular piston enters or enter the pressure area so that the pressure enters the annular space 76 and the annular space Z formed between the piston and a central rod or stalk m screwed or otherwise secured to the cylinder so that the pressure is thus distributed in such a manner that it acts conjointly upon the two heads of the piston latter forward with increased power.

If desired I may provide an air-leak or exhaust n near the enlarged or forward piston-head so as to facilitate the return of the hammer or piston within the cylinder and it will be seen that by my arrangement I provide two areas or surfaces upon which the pressure acts simultaneously so that I thereby increase the power of, the hammer without unnecessarily increasing the diameter of the whole device or unduly increasing its weight. The cutter or cutters for 'cylinder "or body portion to absorb the initial is adapted to work similar to those described with reference to in its portion the tube-cleaning device may be arranged as shown in a manner similar to that described in the specification to my co-pending application or any other suitable form of cutter or cutters may be employed.

Fig. 2 represents a form of device in which the number of joints that are to be kept pressure-tight has been reduced to a minimum thus making the apparatus as fool-proof as possible, and in carrying my invention into effect according to this mode I form the a in one piece and of two different diameters, the cutter or cutters for operating upon the scale being of any desirable form and being secured at the front end of the cylinder or body by means of a-spring a and nut 0 screwed upon the central stalk m passingthrough the cylinder or.body,.a pad of'rubber p being'preferably introduced between the nut and the spring shocks and thus prolong the life of the spring. The stalk or rod is bored for a portion of its length to form a longitudinal passage 0 from which two sets :of radial passages r and s communicate with the exterior ofthe stalk and between the latter and the cylinder an annular piston 22 provided with two heads the foregoing modification and adapted to work respectively within two portions of the cylinder of differing diameter. The forward or striking head is a working fit withof the cylinder while the rearward head is of a diameter slightly less than the internal diameter of its portion of the cylinder to provide the necessary passage for the pressure medium. The piston is provided with one or more slots 2? to control the supply of pressure medium which is admitted to the passage 0 formed in the stalk.

The radial ports 1' insures that a certain amount of pressure w1ll be exerted upon the .inner side of the rearward head of the piston "so'as to have a tendency to force the piston .rearwardly within the cylinder while the pressure medium device passes, when the slots 2, are in the requisite position, by way proper for operating the of the ports or assa es s so as to o erate simultaneousl upon the forward and rearward heads for delivering the cutters.

For the purpose of exhausting the pressure medium'from the device after the operative stroke I provide exhaust ports u in the cylinder, and in addition I may also forma second bore or passage 11 in the forward portion of the central stalk or rod which besides facilitating the exhaust also tends to keep the front of the cutters free required blow upon the from scale. It will be obvious that theslots tin the pistcn serve to permit of the .ex-

z'haustingfromiheccylinder as well ascofthe .and with the front faces supply of pressure medium to the hammer and it will be seen that in the improved construction just described only one pressure joint exists in a readily accessible part of the machine and the whole device is thus made entirely fool-proof.

It will be clear that to the construction shown in Fig. '1 the'stalk or rod m serves merely tohold the cutters in position and is not necessary to the operation of the hammer, it being evident that withadifferent arrangement of cutters the hammer might bemade solid and in consequence, more powerful.

It will be obvious that I do not desireto confine my invention to its application here inbefore given by way of example nor to any particular form or arrangement of pneumatic device that .is to rangement "of cutter or cutters with which moved, and I modify the details of arrangement and the construction of the various parts to suit the particular type of apparatus, the purpose for which the apparatus is to be employed or the particular practical conditions which the invention may be designed'to'meet.

Havingnow described my invention what I claim as new and desire to-secure by Letters Patent is 1. A pneumatic tool comprising a casing having two bores of different diameters, a central member fixed casing and extending to the forward end thereof, a cutting element loosely mounted upon the forward end of said fixed member,

an annular piston surrounding said member and having two heads of different diameters each of which has a rear face and a front face and means for putting a supply of working ifluid into'communication with the rear faces'ofsaidheadson the power stroke on theexhaust or rearward stroke of the hammer.

2. A pneumatic tool'comprising a :casing having two bores of difl'erentdiameters, a

central member secured to the rear end .of

the'casing and extending to the forward end thereof, said central member having a longitudinal passage communicating with the source of supply of working fluid and radial passages therefrom, and a second. separate longitudinal passage at the forward end thereof and radial passages communicating therewith, an annular piston having ports therein surrounding said central member and having its rear end contacting in such a manner as to form an annular chamber between the hammer and the central member, said hammer having two heads :of different diameters working within the two parts ,0fJ.lI118-IC21S,1I1g5..LIld veach, of which be employedv with my apparatus'nor to any particular arto the rear end of said therewith has a rear face and a front face, the arrangename to this specification in the presence of ment being such that the rear faces of the two subscribing witnesses.

heads are in communication with the pressure fluid during the working stroke and the HARRY SAMUEL BIGKERTON BRINDLEY' 5 forward faces during the exhaust or rear- Witnesses:

ward stroke of the hammer. A. J. WORTH, In testimony whereof I have signed my C. P. LLDDON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents, Washington, D. 0. 

